The 1990 United States Senate elections were held on Tuesday, November 6, 1990, with the 33 seats of Class 2 contested in regular elections. Special elections were also held to fill vacancies. The Democratic Party increased its majority with a net gain of one seat from the Republican Party. The election cycle took place in the middle of President George H. W. Bush's term, and, as with most other midterm elections, the party not holding the presidency gained seats in Congress. This was the last election cycle until 2022 where only one U.S. Senate seat flipped parties.
The 1984 United States Senate elections were held on November 6, with the 33 seats of Class 2 contested in regular elections. They coincided with the landslide re-election of President Ronald Reagan in the presidential election. In spite of the lopsided presidential race, Reagan's Republican Party suffered a net loss of two Senate seats to the Democrats, although it retained control of the Senate with a reduced 53–47 majority. Democrats defeated incumbents in Illinois and Iowa, and won an open seat in Tennessee, while Republicans defeated an incumbent in Kentucky.
The 1982 United States Senate elections were held on November 2, 1982. They were elections for the United States Senate following Republican gains in 1980. The 33 Senate seats of Class 1 were up for election in 1982. A total of four seats changed hands between parties, with Democrats winning seats in New Jersey and New Mexico, and Republicans taking seats in Nevada and the seat of the lone independent, Senator Harry Byrd Jr., in Virginia. Democrats made a net gain of one seat bringing them to 46 seats, while Republicans stayed at 54 seats for a majority. However, the Democratic gain in New Jersey replaced a Republican that had been appointed earlier in the year.
The 1978 United States Senate elections were held on November 7, in the middle of Democratic President Jimmy Carter's term. The 33 seats of Class 2 were contested in regular elections. Special elections were also held to fill vacancies.
The 1972 United States Senate elections were held on November 7, with the 33 seats of Class 2 contested in regular elections. They coincided with the landslide re-election of Republican President Richard Nixon. Despite Nixon's landslide victory, Democrats increased their majority by two seats. The Democrats picked up open seats in Kentucky and South Dakota, and defeated four incumbent senators: Gordon Allott of Colorado, J. Caleb Boggs of Delaware, Jack Miller of Iowa, and Margaret Chase Smith of Maine. The Republicans picked up open seats in New Mexico, North Carolina, and Oklahoma, and defeated one incumbent, William B. Spong Jr. of Virginia.
The 1970 United States Senate elections was an election for the United States Senate. It took place on November 3, with the 33 seats of Class 1 contested in regular elections. Special elections were also held to fill vacancies. These races occurred in the middle of Richard Nixon's first term as president. The Democrats lost a net of three seats, while the Republicans and the Conservative Party of New York picked up one net seat each, and former Democrat Harry F. Byrd Jr. was re-elected as an independent.
The 1960 United States Senate elections coincided with the election of John F. Kennedy as president on November 8, 1960. The 33 seats of Class 2 were contested in regular elections. A special election was also held on June 28, 1960, for a mid-term vacancy in North Dakota where Democrats flipped a seat to expand their majority to 66–34. As Majority Leader Lyndon Johnson was elected Vice President, Mike Mansfield became the new majority leader.
The 1958 United States Senate elections were elections for the United States Senate which occurred in the middle of President Dwight D. Eisenhower's second term. Thirty-two seats of Class 1 were contested in regular elections, the new state of Alaska held its first Senate elections for its Class 2 and 3 seats, and two special elections were held to fill vacancies.
The 1932 United States Senate elections coincided with Democrat Franklin D. Roosevelt's landslide victory over incumbent Herbert Hoover in the presidential election. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies.
Floyd Kirk Haskell was an American lawyer and politician. A member of the Democratic Party, he served as a U.S. Senator from Colorado from 1973 to 1979.
The 1912–13 United States Senate elections were held on various dates in various states. They were the last U.S. Senate elections before the ratification of the Seventeenth Amendment in 1913, establishing direct elections for all Senate seats. Senators had been primarily chosen by state legislatures. Senators were elected over a wide range of time throughout 1912 and 1913, and a seat may have been filled months late or remained vacant due to legislative deadlock. Some states elected their senators directly even before passage of Seventeenth Amendment. Oregon pioneered direct election and experimented with different measures over several years until it succeeded in 1907. Soon after, Nebraska followed suit and laid the foundation for other states to adopt measures reflecting the people's will. By 1912, as many as 29 states elected senators either as nominees of their party's primary or in conjunction with a general election.
The 2014 United States Senate election in Colorado was held on November 4, 2014 to elect a member of the United States Senate to represent the State of Colorado, concurrently with the election of the Governor of Colorado, other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections. Incumbent Democratic Senator Mark Udall ran for re-election to a second term, but narrowly lost to Republican U.S. Representative Cory Gardner by a margin of 1.9 percent.
The 1972 United States Senate election in Alabama was held on November 7, 1972.
The 1930 United States Senate election in Maine was held on September 8, 1930. Incumbent Republican U.S. Senator Arthur Gould, who had been elected to complete the term of the late Senator Bert Fernald, did not run for re-election to a full term.
The 2020 United States Senate election in Colorado was held on November 3, 2020, to elect a member of the United States Senate to represent the State of Colorado, concurrently with the 2020 U.S. presidential election, as well as other elections to the United States Senate, elections to the United States House of Representatives and various state and local elections.
The 1972 United States Senate election in Louisiana was held on November 9, 1972.
The 1972 United States Senate election in Arkansas took place on November 7, 1972. Incumbent U.S. Senator John L. McClellan was re-elected to a sixth term in office, defeating U.S. Representative David Pryor in a hotly contested primary. In the general election, McClellan easily defeated Republican physician Wayne Babbitt. This was McClellan's final campaign; he died in his sleep in 1977. Pryor was elected Governor of Arkansas in 1974 and won the race to succeed McClellan in 1978.
The 1972 United States Senate election in Iowa took place on November 7, 1972. Incumbent Republican U.S. Senator Jack Miller ran for re-election to a third term but was defeated by Democrat Dick Clark. Iowa was one of fifteen states alongside Alabama, Arkansas, Colorado, Delaware, Georgia, Louisiana, Maine, Minnesota, Mississippi, Montana, New Hampshire, Rhode Island, South Dakota and West Virginia that were won by Republican president Richard Nixon in 1972 that elected Democrats to the United States Senate.
The 1972 United States Senate election in Mississippi was held on November 7, 1972. Incumbent Democratic U.S. Senator James Eastland won re-election to his sixth term. To date, this was the last time that the Democrats won the Class 2 Senate seat in Mississippi. Mississippi was one of fifteen states alongside Alabama, Arkansas, Colorado, Delaware, Georgia, Iowa, Louisiana, Maine, Minnesota, Montana, New Hampshire, Rhode Island, South Dakota and West Virginia that were won by Republican President Richard Nixon in 1972 that elected Democrats to the United States Senate.
The 1978 United States Senate election in Colorado took place on November 7, 1978. Incumbent Democratic Senator Floyd Haskell ran for re-election to a second term, but was soundly defeated by Republican U.S. Representative William L. Armstrong.
